Moving people out of social exclusion reduces the risk they will commit acts of violence later in life.
Photograph: Alamy

Small improvements in parents’ social mobility can significantly reduce the likelihood of children growing up to commit violent crimes, according to a study of 45,000 young people over nearly two decades.

The chance of children going on to be convicted of violence is almost halved if their family moves from the poorest 20% of society to the next 20% bracket up, according to a study by academics at the University of Manchester based on Danish data, which they argue has UK relevance.

The study, which is published in the Lancet, plots the effects of transitions in family income on violence, as well as self-harm, including suicide, and shows that even small changes in family fortunes at any time in a child’s upbringing can have a positive impact. Equally, children in families whose income falls are more likely to commit violent acts of crime and self-harm, depending on the extent of downward mobility endured by their parents. The longer a child remains in a low-income household, the more likely they are to grow up to commit violent crimes, the study shows.

The findings are likely to fuel debate about the impact of the British government’s austerity programme on violent crime, which rose 17% in the past year. Knife crime has been increasing annually since 2013, and the number of stabbings committed by 10- to 17-year-olds has increased over that period.

Income inequality is also predicted to rise over the next two years by the Institute for Fiscal Studies, as cuts to working-age benefits take effect and real incomes for the poorest 20% fall.

“This takes us away from the relatively pessimistic view that if you are born in poverty,the die is cast,” said Roger Webb, professor of mental health epidemiology at the University of Manchester, who undertook the study with Aarhus University. “If you move people out of social exclusion, even into a still relatively poor environment, it has a marked influence in terms of reducing risk.”

Income appears to be a significant factor because it denotes other influences on child development, such as access to services, housing, the area they live, as well as social status, participation and exclusion, the academics said.

They tracked family income and violent crime, including murder, rape and assault, of 40,000 Danes over an 18-year period. A similar study is not possible using data about UK citizens because tax records are not accessible and cannot be matched with court records.

The academics believe the correlation between improvements in parents’ social mobility and outcomes for children are likely to be even more pronounced in the UK, where income inequality is greater than in Denmark.

The study found that for any parental income level at birth, being upwardly mobile economically was associated with lower risk compared with being downwardly mobile.

The significant effect of the trajectory of family incomes appears to contradict suggestions that antisocial traits such as emotional dysregulation – the inability to modulate emotional responses – are transmitted between generations.

The shadow home secretary, Diane Abbott, said: “There is now a whole body of expert research showing that deprivation, poor housing, poverty and factors such as school exclusion are key determinants of crime in later life. This government has made all these factors worse with its policy of cuts. They have also slashed the number of police at a time when serious violent crime is rising. This is a double blow in the fight against crime.”

The Home Office said its serious violence strategy would address “the root causes of violence by working with a range of agencies to focus on early intervention alongside strong law enforcement.”

It will steer young people away from violence, it said “helping them to change their behaviour and actions before they reach the stage where they are at risk of entering the criminal justice system.”

A separate study conducted by the social research institute NatCen found that the UK population was growing increasingly worried about police losing control of cities. It found 61% of people think it was likely police in our cities would find it impossible to protect our personal safety, and that poorer people were more likely to fear that outcome. Two-thirds of people who identified as working class said they believed it was likely, compared with half of the middle-class people who were asked.